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Business Logic Extensibility for CAP using the CDS-Oyster Code Sandbox

Welcome to the Extensibility Hands-On Workshop at re>≡CAP 2025.

Overview

Description – In this workshop, you'll learn how to implement business logic extensions using CDS-Oyster for the SAP Cloud Application Programming Model.

We’ll explore the CDS-Oyster plugin and how it enables customers to write and deploy untrusted code to a multi-tenant SaaS application.
Key concepts include creating bound and unbound actions, implementing CRUD event handlers, and testing and debugging them locally.

If you’d like a more in-depth look at CAP extension capabilities, switch to the reCAP2024 branch of this repository. There, you'll find a workshop focused on the broader extensibility concept of CAP.

Exercise

Starting with the Incidents Management sample, we’ll walk through the following use case:

• A multi-tenant application (Incidents) is hosted using MTX-S capabilities
• Customers can subscribe to the application
• A tenant wants to extend the application with customer status management
• Incidents for Gold Status customers must be created with high priority
• The UI should provide a simple way to promote customers to Gold Status — and promote all related incidents accordingly
• There should also be a way to promote individual incidents manually

Exercises

• Exercise 1 – Setting up the environment
• Exercise 2 – Setting up extensibility
• Exercise 3 – Extending the data model
• Exercise 4 – Bound Actions
• Exercise 5 – Unbound Actions
• Exercise 6 – Writing CRUD Event Handlers
• Exercise 7 – Test & Debug
• Exercise 8 – Run Locally with WASM
• Exercise 9 – Deploy to MTX
• Exercise 10 – Advanced Topics
• Summary and Outlook

👉 Please proceed to the first exercise to get started.

Requirements

To complete these exercises, you’ll need:

• Access to SAP Business Application Studio or a local installation of VS Code
• A web browser (Google Chrome is recommended)

License

Copyright (c) 2025 SAP SE or an SAP affiliate company. All rights reserved.
This project is licensed under the Apache Software License, version 2.0, unless noted otherwise in the LICENSE file.

Support

Support for this workshop content is available during the live online session for which it has been designed.